Ponente
Dr.
Theopisti Dafni
(Universidad de Zaragoza)
Descripción
Xenon-trimethylamine (TMA) mixtures are particularly interesting in the framework of rare event searches with gaseous Time Projection Chambers (TPC): first because gain measurements indicate that they form a Penning mixture, anticipating a 'supra-intrinsic' energy resolution stemming from the initial ionization and, second, because TMA is known to strongly fluoresce around 300nm, a convenient wavelength for standard photomultipliers (for Xe-TMA the primary scintillation yield is yet unknown, though). In addition, we establish experimentally that, for ~% concentrations nearing the optimum charge Penning-transfer (as estimated from gain measurements), the track blurriness introduced by the transport of the electrons from the decay region to the measuring plane is reduced in about 1 order of magnitude when using such a mixture, as compared with Xenon at the same pressure.
In order to address the main topological characteristics of such a mixture (as derived from its electron swarm transport coefficients), we report the behaviour of a 70-liter Xe-TMA TPC, developed within the framework of the NEXT experiment. The TPC is equipped with novel highly pixelated and low radioactivity microbulk-Micromegas detectors and is being used for pressures ranging from 1-10bar. We include a 3-D characterization at 1, 3 and 10bar both for point-like electron tracks and extended ones from gamma-ray interactions (511keV), of interest in the most appealing next generation Xenon-based experiments.
Autor primario
Dr.
Theopisti Dafni
(Universidad de Zaragoza)
